Deleted files in Windows simply get renamed, I think; they're still there and can be recovered if necessary. Does CC overwrite these files, similar to what Window Washer does?
Hi wjim, Welcome to the forum
You can enable that feature if you want by opening Ccleaner > Options > Settings
On the Secure Deletion area you can set it to overwrite and set the number of passes you want to use (1, 3 or 7)